A gas sensor arrangement is known from DE 10 2005 049 522 B3 having a radiation apparatus, a gas measurement space, a detector apparatus and an evaluation apparatus, wherein the evaluation apparatus controls the radiation apparatus, records and evaluates the detector signals and determines the measured gas concentration in dependence on the output signal of the detector apparatus. The radiation apparatus has at least two measurement radiation sources and at least one reference radiation source which each irradiate the radiation in at least one absorption band of the gas to be detected, in the measurement band, and which irradiate the radiation in at least one spectral band not absorbing the measured gas, the reference band. The detector apparatus is configured such that it can receive the radiation, after its passage through the gas measurement space in a measurement band or in a reference band, independently with respective spatial and/or temporal separation, wherein the evaluation apparatus operates the radiation sources in accordance with a specific control algorithm and determines and compares the output signals of the detector apparatus in the measurement band and/or in the reference band on the switching on of one of the radiation sources or on a radiation source comparison, optionally compensates a possible aging of the gas sensor arrangement and determines the measured gas concentration.
Known infrared gas sensors, for example, have a broadband radiation source, an absorption path or a gas measurement space, a wavelength-selective element, e.g. an optical band pass filter such as an interference filter, a Fabry-Perot interferometer or a grating and a radiation detector, for example a pyroelectric detector, a semiconductor detector or a thermophilic detector. The attenuation of the radiation arriving at the detector due to the absorption by the gas molecules is a measure for the concentration of the gas absorbing at the set wavelength. The wavelength-selective element can be arranged in front of and/or behind the gas measurement space.
The use of a wavelength-selective radiation source such as an LED or a laser in combination with non-wavelength-selective radiation receivers is likewise known.
The radiation absorption by gas molecules in the infrared range is also utilized in photoacoustic gas sensors. The radiation absorption results in a heating of the gas in the gas measurement space. The pressure change resulting from this is registered by means of an acoustic detector such as a microphone or by means of a pressure sensor.